The assignee of the present application owns U.S. Pat. No. 5,564,663, entitled “Transitional Pivot Joint For Head Support Base Unit,” which is expressly incorporated herein by reference, in its entirety (the “'663 patent”). The '663 patent shows a base unit which connects to a medical table. The base unit includes a crossbar and a handle assembly. A transition member connects to the handle assembly, and a swivel adaptor connects to the transition member. Typically, a head holding device, such as a skull clamp or a horseshoe headrest, connects to the swivel adaptor to hold the head of a patient in a desired position relative to the table. Assignee's U.S. Pat. No. 4,169,478, shows a commonly used, well known three-pin skull clamp, and U.S. Pat. No. 5,317,771, shows a well-known horseshoe headrest.
In practical terms, the base unit serves as the intervening hardware that holds the patient's head relative to the medical table. That is, the base unit represents the structural component that connects directly to the medical table, and which in turn supports one or more additional structural components, the last one of which securely holds the head holding device. Usually, the head and upper torso of the patient are cantilevered so as to extend horizontally off the end of the medical table, with the head of the patient fixedly held in place by the head holding device. When the intervening structure of the head holding system includes a base unit, a transition member, and a swivel adaptor, as disclosed in the above-mentioned '663 patent, each of these components is selectively movable relative to each adjacently located component. This enables the neurosurgeon, or the operating room nurse or attendant, to position the patient's head in a desired position relative to the medical table, and then to rigidly clamp these various components together in a desired orientation, to achieve rigid support of the patient's head in the desired position.
More specifically, the base unit has two spaced support rods that connect to the medical table, which in turn support two spaced brackets which hold a horizontal crossbar. A handle assembly of the base unit is oriented transverse to the crossbar, and includes at a first end thereof a first clamp with a first bore that is sized to surround the crossbar. The internal dimension of the first bore is such that the handle assembly may be rotated about the axis of the crossbar, but may also be locked in a fixed position relative to the crossbar when the first clamp is tightened so as to reduce the internal dimension of the bore. The first clamp also enables the handle assembly to be moved horizontally along the crossbar, between the opposing brackets.
The handle assembly of the base unit includes an internal extension bar which extends along an elongated body of the handle assembly, but is fixed adjacent to the first clamp. A lever is pivotally connected to the elongated body, and is also operatively connected to the opposite end of the extension bar. The lever moves relative to the elongated body between: 1) an open unlocked position, in which the bore of the first clamp is enlarged relative to the crossbar and thereby rotatable with respect thereto; and 2) a closed, or locked position in which the internal dimension of the first clamp is reduced to lock the clamp to the crossbar. Thus, movement of the lever between the open and the closed positions enables the handle assembly to be rotatable or fixed, respectively, relative to the crossbar via the first clamp.
The handle assembly also includes a second clamp at a second end thereof, which defines a second bore spaced from and oriented parallel to the first bore. As with the first bore, the second bore has an internal dimension which varies, depending upon the position of the lever relative to the elongated body. The second bore of the handle assembly is sized to removably hold a shaft mounted transversely at one end of the transition member.
Thus, when the lever is in the open position relative to the handle assembly, the handle assembly is rotatable about the first axis, i.e. around the crossbar, and the transition member is also rotatable about a second spaced axis which is parallel with the first. Once rotated to the desired position, these components can be locked in place by closing the lever. The opposite end of the transition member typically includes a combination threaded/star burst connection to enable a first end of a conventional swivel adaptor to connect to the transition member. An opposite end of the swivel adaptor includes another combination threaded/star burst connection, for rigid securement thereto of the desired head holding device. These threaded star burst connections at the opposite ends of the swivel adaptor provide additional maneuverability for this head holding support system.
This combination of selectively movable components, including the intervening clamps and connectors, provides stable and secure fixation of a patient relative to the medical table, with a high degree of reliability and consistency, as is needed for brain surgery. In fact, the head holding devices shown in these U.S. patents are recognized by neurosurgeons around the world as representing the gold standard in terms of achieving a high degree of head fixation and stability with respect to holding the head of a patient during brain surgery. Although others have tried to mimic these head holding devices and these systems, for one reason or another they have not been as successful as assignee, or its predecessor, in consistently achieving the desired degree of patient fixation relative to a medical table.
Despite its long track record of success for these head holding products, assignee seeks to continue to improve upon the performance of such cranial stabilization devices, in an effort to continue to meet the needs of neurosurgeons around the world. But with respect to enhanced maneuverability, this goal is more easily wished for than actually achieved. That is because each additional component requires additional structure for permitting selective movement relative to the adjacently located components, and also the necessary structure for locking the component in the selected position. So adding an additional degree of maneuverability generally requires another connector, and also occupies additional space. Also, in the operating room it can also be important for the operation of these components to be readily understood and user-friendly, so a completely different structure could lack the degree of familiarity of the well-known components currently used.
Also, in some instances, the time and convenience of maneuvering these head holding components into the correct position can be critical. Because of the multiple connection points of the various intervening components, it is possible that inexperienced operating room personnel may initially connect the components in an incorrect manner, such that the components need to be disconnected and then properly connected in order to securely hold the patient in the desired position. Also, some of these intermediate pieces come in different sizes. For instance, the transition member typically comes in two standard lengths, three inches and six inches. Such size variations can create questions among operating room personnel as to the most preferred, or most appropriate, components to use for holding a patient in a particular situation.
It is one object of the invention to enhance the flexibility and versatility of a head holding structure used to maneuver and support a patient in a desired position at the end of a medical table.
It is another object of the invention to simplify the decisions, the procedures, and/or the components needed by neurosurgeons or operating room attendants for correctly locating a patient's head in a desired position relative to the end of the medical table, and then firmly securing the patient's head in that desired position.
It is still another object of the invention to accomplish these objectives with structure that is reasonably familiar to neurosurgeons and operating room personnel, and which does not occupy an excessive amount of three dimensional space.